1. Technical Field
The present invention relates to a refrigerant recovery processing and storage unit, and more particularly to a recovery processing and storage unit and method wherein pressurized gas is utilized to remove any type of halogenated (HFC) or chlorinated (CFC) fluorocarbon refrigerant from small, medium or large sized air conditioning and refrigerating units.
2. Description of the Prior Art
Air conditioning and refrigeration systems (AC&R) make use of many types of HFC's or CFC's as the working refrigerant fluid. When the systems need to be repaired, the refrigerant fluid is generally released to the atmosphere, causing the breakdown of the ozone layer, which allows harmful radiation to reach the earth. Since such releases of refrigerant fluids are now or soon will be illegal, a way to remove refrigerant from the AC&R's without releasing them to the atmosphere is desired.
Refrigerant recovery processes and systems are known in the prior art, for example, as described in U.S. Pat. No. 4,476,688 to Goddard, refrigerant is pumped directly from a non-functional refrigeration unit by a compressor. In particular, the refrigerant drawn from the refrigeration unit is directed through an oil trap and an acid purification filter dryer to remove lubricating oil and other impurities before the refrigerant gas enters the compressor. The refrigerant drawn from the unit is compressed and passed through a condenser coil where the hot compressed gas is converted to a liquid. The liquified refrigerant is directed to a receiving tank and is discharged therefrom directly back into the refrigeration unit when repaired. In addition, some of the liquified refrigerant is returned to the condensing coil to effect condensation of the heated gaseous refrigerant flowing therethrough.
In U.S. Pat. No. 4,766,733 to Scuderi, a system is shown in which a standard refrigerant receiver is disposed in a circuit between a refrigeration system to be evacuated, and a compressor of a reclamation unit. The receiver includes a first port linked to a tube extending generally down to the bottom of the receiver, a second port linked to a second tube which extends only partially into the receiver, and a third port linked to a tube also extending generally down to the bottom of the receiver. During evacuation of the refrigerant from the unit, the first port is linked to the outlet of the system to be evacuated, and the second port is linked to a port leading to the inlet of the compressor. The third port is closed. The interior of the receiver charges with a small amount of refrigerant gas until the pressure in the receiver is equal to the pressure in the system to be evacuated.
The compressor is turned on, and refrigerant gas from the top of the receiver is drawn through the second tube and into the inlet of the compressor and thereafter enters the condenser. Removal of the gaseous refrigerant from the receiver has the effect of lowering the pressure in the receiver, which boils off a small amount of the liquid refrigerant at the bottom of the receiver which tends to cool the refrigerant entering the receiver from the system to be evacuated. Since the refrigerant in the receiver is constantly cooled, the pressure in the receiver is always maintained below that of the system to be evacuated until all of the refrigerant is removed.
When the system has been completely evacuated and serviced, the outlet of the compressor is linked to the third port of the receiver, and the first port of the receiver is connected to the inlet of the system from which the refrigerant has been evacuated. The second port of the receiver, that is, the port connected to the short tube is linked to the inlet of the compressor. The compressor is turned on, and the refrigerant gas is drawn from the receiver, compressed in the compressor and thereafter returned to the receiver as a heated and compressed gas through the third port. The heated and compressed gas warms the liquid refrigerant at the bottom of the receiver, thereby increasing the pressure in the receiver and causing liquid and gaseous refrigerant to flow out of the first port and back into the system to be charged.
The known prior art systems are typically small portable units designed for automobile air conditioning and home appliance applications. During operation the compressor directly contacts the refrigerant which is being pumped from the refrigeration system. Since the known systems all use a compressor to remove the refrigerant from the system, and since compressors can generally only be designed to be used with one specific type of refrigerant, that is, compressors are unique for either low, medium or high pressure refrigerants, the overall recovery systems are limited to recovery of only a specific type of refrigerant.
For example, the above discussed prior art is limited to removal of CFC R12. Additionally, the above prior art systems are only useful for removing small quantities of refrigerant from small systems, typically less than four pounds. Furthermore, since compressors are designed to be used only with specific lengths of suction hose line, the applications of the above systems are limited to refrigeration systems from which refrigerant may be conveniently evacuated with certain hose lengths. The design of the systems is further complicated by the fact that only refrigerant in the gaseous state may enter the compressor. If liquid refrigerant enters the compressor, damage will occur. Finally, the known prior art systems cannot be constructed to ensure that no refrigerant escapes from the system and enters the atmosphere.